docs: def _initialize_session():
      # type: () -> None
      """
      Generate a new session key and store it to thread local storage.
      """
      sys_random = random.SystemRandom()
      _thread_local_storage.secret_key = b''.join(
          int2byte(sys_random.randint(0, 255))
          for _ in range(SECRET_KEY_BITS // 8))